Mitochondrial ND5 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy in a Chinese pedigree

Hypertrophic cardiomyopathy is a primary disorder characterized by asymmetric thickening of the septum and left ventricular wall, which affects 1 in 500 individuals in the general population. Mutations in mitochondrial DNA have been found to be one of the most important causes of hypertrophic cardiomyopathy. Here we report the clinical, genetic and molecular characterization of a Han Chinese family with a likely maternally transmitted hypertrophic cardiomyopathy. Four (2 men/2 women) of 5 matrilineal relatives in this 3-generation family exhibited the variable severity and age at onset of 44 to 79years old. Sequence analysis of the entire mitochondrial DNA in this pedigree identified the known homoplasmic ND5 12338T>C variant. This mitochondrial DNA haplogroup belongs to the Eastern Asian F2a. The 12338T>C variant, highly evolutionarily conserved, resulted in the replacement of the translation initiating methionine with a threonine, shortening the ND5 polypeptide by 2 amino acids. The occurrence of ND5 12338T>C variant exclusively in maternal members of this Chinese family suggested that the 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy. Our findings will provide theoretical basis for genetic counseling of maternally inherited hypertrophic cardiomyopathy.     

Revision of the Euthalia phemius complex (Lepidoptera: Nymphalidae) based on morphology and molecular analyses

Adults of the Euthalia phemius complex, which is composed of three South‐East Asian nymphalid species, Euthalia phemius, Euthalia ipona, and Euthalia euphemia, were genetically analysed by examining mitochondrial and nuclear genes. The E. phemius complex was also examined morphologically, with particular emphasis on wing markings and male genitalia. No significant differences amongst the three species in the complex were detected with respect to either genetic distance or genital morphology. We therefore conclude that the three currently recognized Euthalia species belong to a single species. Accordingly, E. ipona is synonymized with E. phemius. Euthalia euphemia is treated as a subspecies of E. phemius. Type specimens of all taxa and a synonymic list for the E. phemius complex are also given. In addition, we briefly discuss the evolution and biogeography of the species complex. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 304–327.     

粪肠球菌Ace重组蛋白的表达、纯化及黏附活性研究

构建含粪肠球菌表面蛋白Ace保守序列A的重组载体,在大肠埃希菌M15中进行诱导表达、纯化表达产物,研究其黏附活性。以粪肠球菌标准株JH2-2为模板进行PCR扩增ace基因保守序列A,构建重组质粒pQE30/Ace,转化至表达宿主菌M15中进行诱导表达,利用SDS-PAGE和Western blot进行分析和鉴定表达结果,Ni-NTA亲和层析柱纯化重组蛋白,同时用纯化的Ace重组蛋白免疫新西兰兔,用所得相应的抗血清分别进行黏附和黏附抑制实验。结果可见,构建的重组质粒经酶切鉴定和测序鉴定证明其中插入片段为ace基因保守序列A,测序结果与Genbank上登录序列完全一致;SDS-PAGE分析显示,重组工程菌表达了一相对分子质量(Mr)约为37 ku的目的蛋白条带,Western blot检测其能与6×His单克隆抗体发生特异性反应。粪肠球菌JH2-2能够黏附于胶原蛋白Ⅰ表面;抗Ace多克隆抗体可抑制46℃培养的JH2-2对胶原蛋白Ⅰ的黏附,这种抑制作用与其稀释度呈负相关。构建的原核表达载体PQE30/Ace在E.coli M15中成功地表达,纯化的重组Ace蛋白具有胶原黏附活性。     

Recognition of aminoacyl-tRNA: a common molecular mechanism revealed by cryo-EM

The accuracy of ribosomal translation is achieved by an initial selection and a proofreading step, mediated by EF-Tu, which forms a ternary complex with aminoacyl(aa)-tRNA. To study the binding modes of different aa-tRNAs, we compared cryo-EM maps of the kirromycin-stalled ribosome bound with ternary complexes containing Phe-tRNA^Phe, Trp-tRNA^Trp, or Leu-tRNA^LeuI. The three maps suggest a common binding manner of cognate aa-tRNAs in their specific binding with both the ribosome and EF-Tu. All three aa-tRNAs have the same ‘loaded spring' conformation with a kink and twist between the D-stem and anticodon stem. The three complexes are similarly integrated in an interaction network, extending from the anticodon loop through h44 and protein S12 to the EF-Tu-binding CCA end of aa-tRNA, proposed to signal cognate codon–anticodon interaction to the GTPase centre and tune the accuracy of aa-tRNA selection.     

RanBPM is expressed in synaptic layers of the mammalian retina and binds to metabotropic glutamate receptors

In the central nervous system, synaptic signal transduction depends on the regulation of neurotransmitter receptors by interacting proteins. Here, we searched for proteins interacting with two metabotropic glutamate receptor type 8 isoforms (mGlu8a and mGlu8b) and identified RanBPM. RanBPM is expressed in several brain regions, including the retina. There, RanBPM is restricted to the inner plexiform layer where it co-localizes with the mGlu8b isoform and processes of cholinergic amacrine cells expressing mGlu2 receptors. RanBPM interacts with mGlu2 and other group II and group III receptors, except mGlu6. Our data suggest that RanBPM might be associated with mGlu receptors at synaptic sites.     

响应面法优化弗氏链霉菌S-221变种发酵培养基

用响应面法对弗氏链霉菌S-221变种液体发酵生产氨基酸的培养基进行了优化。首先,用全因子试验方法对相关影响因素的效应进行评价,并筛选出有显著效应的羽毛胨和蛋白胨两个因素,第2步用最陡爬坡实验逼近以上两因素最优水平。最后由中心组合设计法及响应面分析确定主要影响因素的最佳条件。在优化培养条件下,发酵液中氨基酸浓度从4.1g／100mL提高到6.412g／100mL。     

Geochemical baseline determination and pollution assessment of heavy metals in urban soils of Karachi,Pakistan

Karachi is one of the most populated urban agglomerations in the world. No categorical study has yet discussed the geochemical baseline concentrations of metals in the urban soil of Karachi. The main objectives of this study were to establish geochemical baseline values and to assess the pollution status of different heavy metals. Geochemical baseline concentrations of heavy metals were estimated using the cumulative frequency distribution (CDF) curves. The estimated baseline concentrations of Pb, Cr, Cu, Zn and Fe were 56.23, 12.9, 36.31, 123.03 and 11,776 mg kg⁻¹, respectively. The pollution status of heavy metals in urban soils was evaluated using different quantitative indices (enrichment factor–EF, Geo-accumulation Index–I_geo, and pollution index–PI). Enrichments factors of the selected heavy metals determined by using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. The urban soils of Karachi were found to have a moderate to moderately severe enrichment with Pb, whereas Cr and Cu has moderate and Zn has minor enrichment. I_geo results indicated moderate soil contamination by Pb at some of the sampling locations. PI for Pb, Cr, Cu and Zn was found in the range of 0.04–3.42, 0.19–1.55, 0.27–2.45 and 0.32–1.57, respectively. Large variations in PI values of Pb revealed that soil in those areas of the city which are influenced by intensive anthropogenic activities have exceptionally high concentrations of Pb. The findings of this study would contribute to the environmental database of the soil of the region and would also facilitate both at the local and the international scales, in a more accurate global environmental monitoring, which will eventually facilitate the development of management and remediation strategies for heavy metal contaminated urban soil.     

Inhibition of EF-G dependent GTPase by an aminoterminal fragment of L7/L12.

The E. coli ribosomal proteins L12 and its N-acetylated form L7 were cleaved into an N-terminal and C-terminal fragment of roughly comparable size. The selective cleavage at the lone arginine residue was accomplished by trypsin treatment of the citraconylated proteins, followed by removal of the citraconyl moieties. These fragments, both separately and in combination, were incapable of reconstituting elongation factor G (EF-G) dependent GTPase of CsCl ribosomal cores supplemented with L10. However, incubation of cores containing L10 with the N-terminal fragment prevented the reconstitution of GTPase activity by intact L7/L12. No inhibition was observed when CsCl cores lacking L10 were incubated with the N-terminal fragment followed by addition of a preincubated mixture of L7/L12 and L10. The results indicate that the N-terminal part of L7/L12 is responsible for its ability to bind to 50S ribosomes and that L7/L12 together with L10 form a protein cluster on the ribosome.     

Direct Evidence of an Elongation Factor-Tu/Ts·GTP·Aminoacyl-tRNA Quaternary Complex

During protein synthesis, elongation factor-Tu (EF-Tu) bound to GTP chaperones the entry of aminoacyl-tRNA (aa-tRNA) into actively translating ribosomes. In so doing, EF-Tu increases the rate and fidelity of the translation mechanism. Recent evidence suggests that EF-Ts, the guanosine nucleotide exchange factor for EF-Tu, directly accelerates both the formation and dissociation of the EF-Tu-GTP-Phe-tRNA^Phe ternary complex (Burnett, B. J., Altman, R. B., Ferrao, R., Alejo, J. L., Kaur, N., Kanji, J., and Blanchard, S. C. (2013) J. Biol. Chem. 288, 13917–13928). A central feature of this model is the existence of a quaternary complex of EF-Tu/Ts·GTP·aa-tRNA^aa. Here, through comparative investigations of phenylalanyl, methionyl, and arginyl ternary complexes, and the development of a strategy to monitor their formation and decay using fluorescence resonance energy transfer, we reveal the generality of this newly described EF-Ts function and the first direct evidence of the transient quaternary complex species. These findings suggest that EF-Ts may regulate ternary complex abundance in the cell through mechanisms that are distinct from its guanosine nucleotide exchange factor functions.